Driving gear for bicycles



Nov. 2- c. J. ENGLERT DRIVING GEAR FOR BICYCLES Filed Nov. 14', 1940 3Sheets-Sheet 1 g v Inventoi' Attorney M Nov. 10, 1942.

Filed Nov. 14, 1940 C. J. ENGLERT DRIVING GEARAFOR BICYCLES aShejets-Sheet 2 1 1 iiilinif ii in'iil @IIIIRIIHI mfii'illlllllllll!@IIIIIIIII IIIIIIIIEMHI Fig- 7 Fig 5 Inventor g I [0H0Nov. 10, 1942. c. J. ENGLERT DRIVING GEAR FOR BICYCLES Filed Nov. 14,1940 3 Sheets-Sheet 3 Inventor LU flitorney Patented Nov. 10, 1942UNITED STATES PATENT OFFICE DRIVING GEAR FOR BICYCLES Conrad J. Englert,Schenectady, N. Y.

Application November 14, 1940, Serial No. 365,690

9 Claims.

This invention relates to the driving gear for bicycles and the generalobject of the invention is to provide such a gear constructed to givethe bicycle rider a mechanical advantage on the working stroke of thepedals.

In the ordinary bicycle the pedals and pedal arms rotate about the axisof the driving sprocket and the rate of motion of the pedals andsprocket are the same throughout a revolution of the latter. The up orreturn stroke of the pedal requires the same time as the down or workingstroke and the pedal remains at the same radial distance from thesprocket axis at all times. When the pedal arms are horizontal theleverage is most favorable, but the length of the lever arm is limitedby the distance between the ground and the sprocket axis.

It is an important object of my invention to mount the pedals and theirarms so they turn about an axis located forwardly of the sprocket axisand provide driving connections between the pedal arms and sprocket. Bythis arrangement the vertical stroke of the pedal remains as usual butthe pedal arm when horizontal places the pedal at a distance from thesprocket axis greater than the length of the pedal arm. A mechanicaladvantage is thereby gained on the working stroke but the high and lowpositions of the pedals are the same as in the ordinary bicycle.

In the usual bicycle the sprocket and pedal arms are fastened togetherand one revolution of the pedals produces one revolution only of thesprocket. In my present invention I introduce a gear and pinionconnection between the sprocket and pedal arms so proportioned as tocause the sprocket to turn faster than the pedals, thereby takingadvantage of the increased power growing out of the eccentric mountingof the pedal arms. Where desired, however, the gearing can be in suchratio as to cause one revolution of the sprocket for each turn of thepedals.

With these and other objects in view which will appear as thedescription proceeds, my invention resides in the combination andarrangement of parts hereinafter described and set forth in the claims.

In the accompanying drawings, where two forms of my invention are shown,

Fig. 1 is a side elevation of the preferred form of my invention, onepedal being in high position at the beginning of a down working stroke,

Fig. 2 is a back elevation of the structure shown in Fig. 1, both pedalsbeing illustrated,

Fig. 3 is a vertical section, on an enlarged scale, on line 33, Fig. 1,

Fig. 4 is a detail vertical section on line 4-4, Fig. 1, enlarged, V

Fig. 5 is a side elevation of the gear and pinion case seen in Fig. 1,

Fig. 6 is a vertical section on line 6-6 of Fig. 5,

Fig. 7 is a detail vertical section on line 1-1, Fig. 1, enlarged,

Fig. 8 is a view similar to part of Fig. 6 showing a modified form ofthe invention,

Fig. 9 is a cross section through the rear wheel of a bicycle showingthe relation between the spokes and their supporting plates, and

Fig. 10 is a plan view showing the rear wheel of Fig. 9 on a reducedscale and the manner in which it is connected to the driving mechanismby the chain.

In illustrating my invention I have not thought it necessary to show thewhole frame and wheels of the usual bicycle, but have shown three framebars III, which support the matter to be described hereinafter. Thesebars are of usual location on the bicycle, and being supported by thewheels, not shown, afford a mounting for my invention. The bars aredirectly connected to a casing II, as suggested in Fig. 5, having acylindrical form with its axis occupying the same place as the sprocketaxis of the usual bicycle. The casing comprises a circular shell I2,having right and left end plates l3 and M, respectively, as viewed inFig. 6, secured to the casing as at,|5 to form a closed chamber [6.

Extending concentrically through the chamber is a driving shaftdesignated at H, the ends of which are substantially alike. Each end istapered as at 18, see right side of Fig. 6, and

fastened thereto is a hub I9, which is tapered internally to fit the endof shaft I! and is held in place by a screw 20, threaded into the end ofthe shaft, and engaging a hub-shoulder 2|. The outer cylindrical surfaceof the hub carries the inner ring of a ball race 22, the outer race 23of which is received by a bearing seat 24, which is formed integral withplate [3. In a similar way the left end of the shaft carries a hub 25,the outer ball race at that end being housed in a race seat 26, integralwith plate It. The shaft I! is thus mounted to rotate freely andconcentrically on balls 21 with respect to the supporting casing.

Secured to the shaft [1 between the two hubs on the shaft is a gear 28,held against a collar 29 on the shaft by a nut 30. The gear 28 turnswith the shaft and meshes in with a pinion 3|, which is'fast on astud-shaft 32, the left end of which is driven into an inner ball race33, the corresponding outer race 34 of which is housed in a seat 35,formed on plate i i, and balls 36 complete the bearing.

At the right of pinion (ii is a second ball bearing, having inner andouter races 31 and 38, respectively, which gives additional bearing forthe stud-shaft 32. Race 38 is located in a race seat 39, formed on theright plate I3. A dust plate it is set into the lower part of the platel 4, to protect the left end of the stud shaft and its bearings. Thereis a bottom cover 4! to the casing H, which is held in place by screws12. This arrangement holds the ball races 3 and 33, and the dust plate49, firmly in place.

The right end of the stud-shaft has secured thereto a second pinion 43,which meshes in with a ring gear at, which in turn is fastened atseveral points as at 5 to the driving sprocket 45. A fiange i? on thesprocket fits closely to the inner surface of the ring gear it andreceives an outer ball race 8 for balls 19, the inner corresponding race56 is driven onto a shouldered race seat integral with plate 53. Thereis sufficient clearance between the sprocket and pinion i3 and a dustguard at 52 to permit free rotation without frictional engagement withthese parts. The sprocket will be connected by the usual chain, notshown, to the rear wheel of the bicycle. M is shown in Fig. 6.

From the matter thus far described, it will be seen that rotation ofshaft 51 will turn drive gear 28, also pinions 3i and 43, and the ringgear 44 which drives the sprocket wheel. shows the preferred form of theinvention, wherein pinions 3! and 53 are of equal diameters, hence onerotation of gear 28 will cause one rotation of the sprocket.

The mechanism for driving the shaft H is shown more particularly inFigs. 1 and 2. As in the usual bicycle, I provide two pedals, one oneach side of the fixed casing, and set them 180 apart on their axis.

Unlike the usual construction, however, the pedals do not rotate aboutthe axis of the sprocket wheel, but are mounted so that their axis is infront of the shaft H, the pedals and parts associated with them are thesame on both sides of the casing H, and include an inner ring 5 3, whichis secured to the adjacent casing sideplate, so that it is fixed withrespect to the vehicle frame.

This inner ring E i is fitted to a seat 55, which is provided on theadjacent casing side plate l3 and secured thereto at tapped out holes56, with screws 5?, as shown in Figs. 1 and 5. Rotatable around eachring 54 is a second ring 58, which rolls on balls til. The inner racefor balls 59 is formed in part by ring 54, as at (it, and in part by aseparate ring ti, which is secured to the inner ring by screws t2, asshown in Fig. 4-. The rings have concentric concave surfaces to receivethe balls 5d, the outer ring 58 moves with a, minimum of friction.

Secured to each outer ring 58 is an arm 63, the outer end of which isshown in detail in Fig. 3. This arm 83 has a cupped bearing seat 64receiving an outer ball race 65, while the inner race is formed of tworace-forming elements 56, which are driven on the reduced end Bl of apedal stud-shaft 68, after the balls 69 are in place. A nut 70 isthreaded on the inner end 3-! cf thestud-shaft 68, which holds theelements At 53 an exposed tooth of ring gear Fig. 6

pedal, shown conventionally at 13.

66 against the stud-shoulder H of the larger part of the stud shaft 68.

An internal nut 12 is threaded into the cupped bearing seat 54, whichholds the outer 65 in place. The stud 68 is extended throughout the footThe pedal and stud shaft 68, therefore, rotate around the fixed ring 55When the rider operates the pedals in the usual manner.

In Fig. 1, the vertical lines A-A and 13-3 pass through the axis of theshaft I? and ring 54, respectively.

Stud 68, therefore, rotates in a path eccentric with respect to theshaft i1, and when it is in front of the shaft it is farthest from it,and is nearest to the shaft when it is behind it. In order tocommunicate motion from the pedal to the shaft, some account must betaken of the eccentric path of the pedal. As shown herein, I provide asliding driving connection between the stud 88 and shaft ll.

Returning to Fig-6, each hub i9 and 25 is formed integral with an innerblock 14. Each of these blocks is associated with a second similar block1'5, spaced outwardly from its companion.

Between these blocks lie rolls 75, with peripheries V-shaped as at 11.Fig. 7 shows the mounting for a roll. A bearing 78 extends through theblock Hi and has a head 78 set into the block. A screw 80 extendsthrough the other block 15 and is threaded into the bearing 13. Thescrew 88 has a head 8:, which is set into the block 15, and the heads 19and 8! hold the two blocks together. Rctataole around each bearing 18 isone of the rolls l6 and ball bearings 82 at each of their sides, topermit free turning of the rolls on their centers. It being the duty ofthese side-ball-bearings 82 to prevent friction due to side strainssubjected to these parts.

Each pair of blocks forms in effect a crank arm on the shaft I7. As seenin Fig. 1, the greater part of the length of the crank arm lies at oneside of the shaft ii, and from Fig. 2 it is seen that the crank arms,one at each side of easing H, project in opposite directions. Each crankarm is caused to turn by a connector 83, having a head 84 into which thelarge part of the corresponding stud 68 is threaded.

The connector 83 extends from its head towards the blocks on the sameside of the casing H and is slotted as at 85, the parallel sides 35,which form the slot having ribs V-shaped in crosssection, to fit theperipheries ll of the rolls it. The slot 85 is of such length as topermit a complete rotation of the stud 68, without interference betweenthe blocks and the connector.

In operation, the rider of the bicycle will turn the pedals in the usualmanner, in the direction of arrow a, as shown at the top of Fig. 1,around the center of ring 54 as an axis. Starting from the positionshown in Fig. 1, the pedal will move to the right, along a path whichmoves away from the shaft ll, causing the slotted part of the connector83 to move in a direction to increase the length of the power arm of theconnector, which acts on its blocks or crank arm. The rider is thereforeat an advantagefwhich increases until the pedal reaches the horizontalline C, at a position in front ofthe shaft 11. As the pedal continues toturn, it starts to move back toward the shaft, the advantage diminishinguntil the pedal crosses line 3-3, after which the down motion of thepedal ceases. At this time, the other pedal is in high position, and itis pushed down in turn to repeat the motion and eifect on shaft I! ofthe pedal already described.

Throughout the downward working stroke of each pedal, except at theinstant of starting and finishing, the power arm represented by theeffective length of the connector in descent is longer than could beobtained with the usual bicycle drive, without excessive permanentlengthening of the pedal arms. The turning of the blocks causes turningof the shaft I1 and the sprocket to drive the vehicle, as alreadydescribed.

If fuller advantage is to be taken of the relationship alreadydescribed, the gearing shown diagrammatically in Fig. 8 may be used.

This figure is similar to Fig. 6, but instead of having the two pinionsand gears of equal diameters, that shown in Fig. 8, which shows thepinion 90 to be smaller in diameter than pinion 3|, shown in Fig. 6, andthe driving gear BI is shown to be necessarily larger in diameter thanthe drive gear 28, shown in Fig. .6, hence the stub-shaft 32 now turnsfaster than in the preferred form, shown in Fig. 6. The actual amount ofthe different speed ratios may be determined by the ratio of thediameters of the driven pinions, and the ratio of the diameters of thedriving gears.

Because of the relation between the pedal, the eccentric ring, and thesprocket wheel, shown particularly in Fig. 2, the chain is spacedfarther from the riders pedal than usual, being nearer the center-lineof the bicycle frame than ordinarily. As a result of this relationship,the sprocket pinion I is nearer the central plane of the driven rearwheel than customarily, and therefore, provision must be made foraccommodating this condition to the spokes of the rear wheel of thebicycle, as shown in Fig. 9, the hub -IOI of the rear wheel, designatedgenerally at I02, has a relatively small ring or flange I03 secured atone end thereof, while the sprocketpinion I00 is secured to the otherend thereof. A relatively large ring or flange I04 is secured to the hubIIII, between the sprocket pinion I00 and flange I03, as suggested inFig. 9. The long spokes I05 connect to the small flange I03, and the rimI06 of the wheel I02, forming with the central plane of the wheel, somesuch angle as that designated at a, in Fig. 9. In that figure, the dotand dash line represents the central plane of the weave. In order thatthis same angle may be formed by the spokes I08, I use the large flangeI04, connecting the short spokes I08 to the periphery of the largeflange, thus preserving the same angle between the central plane of thewheel and the short spokes I08, as that indicated at a.

The reason for the large flange I04 will be apparent from Fig. 10, wherethe dot and dash line IIO represents the central plane of the rear wheeland of the driving mechanism. The chain H2 is driven by the sprocket 46and drives the sprocket-pinion I00.

By the disposition of the short spokes I08 and the large flange I04, assuggested in Fig. 10, I am enabled to place the driving pedalssymmetrically with respect to the center of the bicycle, which in Fig.10 is indicated by line H0.

From the foregoing, it will be seen that I have provided a driving gearfor bicycles, wherein the pedals move around an axis in front of thesprocket axis. It will be seen also that power is transmitted to theshaft I"! through a sliding connection which provides the advantage ofthe eccentric relationship to be communicated to the shaft I'I. Further,the gearing within the casing transfers the rotation of the shaft to thesprocket either by a 1 to 1 relation, as that shown in Fig. 6, or bymeans of the driving gear SI, and pinions and 43 as that shown in Fig.8, which is with a mechanical advantage.

It will further be understood that I have modified the rear wheel of thebicycle to permit a symmetrical arrangement of the driving pedals, andto preserve the same angle between the right and left spokes of the rearwheel I02 with respect to the central plane of the bicycle, as suggestedin Fig. 10, by using a relatively large flange or ring I04 to which theshort spokes I08 are attached. With such an arrangement, the plane ofthe driving chain can be kept parallel with the central plane of thebicycle, and sufficient room provided for the rear sprocket and thedriving chain.

Having thus described my invention, it will be seen that changes andmodifications may be made therein, by those skilled in the art withoutdeparting from the spirit and scope of the invention, and I do not wishto be limited to the details herein disclosed.

But what I claim is:

1. In driving gear for a bicycle having a frame, a hollow casing fixedwith respect to the frame, a shaft extending therethrough and supportedby each side of the casing, means to rotate the shaft, a relativelylarge gear secured to the shaft and located within the casing, a pinionmeshing with the ear, a stub shaft to which the pinion is securedrotatable about an axis fixed with respect to the casing, a secondpinion outside the casing secured to the stub shaft, 2. ring gearoutside the casing meshing with the second pinion outside the casing,and a driving chain sprocket wheel secured to the ring gear.

2. In driving gear for a bicycle having a frame, a casing supported bythe frame, a driving haft extending through the casing and supported byeach side of the casing and rotatable with respect thereto, a gearsecured to the shaft within the casing, a stub shaft rotatable on thecasing, a pinion secured to the stub shaft and meshing with said gear, asecond pinion outside the casing secured to the stub shaft rotating withthe first pinion, a ring gear meshing with a second pinion outside saidcasing, means to mount the ring gear for rotation with respect to andoutside the casing, and a driving chain sprocket wheel secured to thering gear.

3. In a driving gear for a bicycle having a frame, a hollow casingsupported by the frame, a shaft extending through and supported by eachside of the casing and rotatable with respect to the casing, a pair ofdriving arms secured to the shaft, one located on each side of thecasing, a gear within the casing secured to the shaft, a stub shaftextending through and rotatable with respect to the casing, a pinionwithin the casing secured to the stub shaft and meshing with the gear, asecond pinion secured to the stub shaft outside the casing, a ring gearoutside the casing meshing with the second pinion, means to mount thering gear for rotation with respect to the casing, and a driving chainsprocket wheel secured to the ring gear, the ring gear and sprocketwheel being located between the casing and one of said driving arms.

4. In a driving gear for a bicycle having a frame, a hollow casingsupported by the frame, a shaft extending through and supported by eachside of the casing and rotatable with respect to the casing, a pair ofdriving arms secured to the-shaft, one located on each side of thecasing, a drive gear within the casing secured to the shaft, a stubshaft rotatable with respect to the casing, a pinion secured within thecasing to the stub shaft and meshing in with the gear, a second pinionsecured to the stub shaft, a ring gear meshing in with the second pinionoutside the casing, means to mount the ring gear outside the casing forrotation with respect to the casing, and a driving chain sprocket wheelsecured to the ring gear, the ring gear being located between the'saidcasing and one of the said driving arms.

5. In a bicycle driving gear, a frame for the bicycle, a hollow casingsupported by the frame, a shaft extending through the casing androtatably mounted on each side of said casing, a pair of pedal armsmounted to rotate eccentrical- 1y with the shaft, means to cause theshaft to rotate with a constant speed as the pedal arms rotate variably,a gear within the casing secured to the shaft, a pinion meshing in withthe gear and rotatable with respect to the casing, a second pinionoutside the casing rotating with the first pinion and having a diameterdifferent from the first named pinion, a second gear outside the casingmeshing in with the second pinion, and a driving chain sprocket wheelsecured to the second gear.

6. In a driving gear for a bicycle having a frame, a casing secured tothe frame, a shaft extending through and supported by and rotatable withrespect to each side of the casing, a pair of pedal arms rotatable abouta given axis, means to cause the said shaft to rotate with a constantspeed when the pedal arms rotate variably, the said pedal arms rotatingabout a center in front of the axis of the shaft with respect to thebicycle frame, a gear of given diameter within the casing secured to theshaft, a pinion of smaller diameter than the second pinion, meshing inwith the gear, and rotatable with respect to the casing, a second pinionoutside the casing rotating with the first pinion, a second gear smallerin diameter than the first gear outside the casing, meshing in with thesecond pinion of a larger diameter than the first pinion, and a drivingchain sprocket wheel secured to the second gear.

7. In a driving gear for a bicycle having a frame, a hollow casinghaving spaced sides fixed with respect to the frame, a shaft extendingthrough the casing and supported by each of said sides, means to rotatethe shaft, a relatively large gear secured to the shaft within thecasing and located between said sides, a pinion in the casing meshingwith the gear, a stub shaft rotatably mounted with respect to the casingand to which the pinion is secured, a second pinion secured to the stubshaft, a ring gear rotatably mounted on the exterior of one of saidsides of the casing and meshing with the second pinion, and a drivingchain sprocket wheel secured to the ring gear.

8. In a driving gear for a bicycle having a frame, a hollow casinghaving spaced vertical walls mounted on the frame, a shaft extendingthrough the casing and supported by each of the walls, means to rotatethe shaft, a relatively large gear secured to the shaft between saidwalls, a pinion meshing with the gear, a stub shaft rotatably mountedwith respect to the casing and to which the pinion is secured, a secondpinion secured to the stub shaft, a ring gear meshing with the secondpinion, an annular bearing on the outside of one of said walls on whichthe ring gear is rotatably mounted, and a driving chain sprocket securedto the ring gear, said annular bearing and ring gear lying between thesprocket wheel and the adjacent wall of the casing.

9. In a driving gear for a bicycle having a frame, a hollow casing fixedto the frame and having spaced vertical walls, a shaft extendinghorizontally across the casing and rotatably mounted with respect toeach of the walls, means to rotate the shaft, a relatively large gearsecured to the shaft between said walls of the casing, a stub shaftparallel to the first named shaft and rotatably mounted with respect tothe casing, a pinion on said stub shaft meshing with the gear, a secondpinion on said stub shaft, said stub shaft and pinions rotating as aunit, a ring gear meshing with the second pinion, an annular bearing onthe outside of one of the walls of the casing for said ring gear, saidannular bearing lying in a plane between the ends of the first namedshaft and the latter having one end thereof passing through said annularbearing, and a driving chain sprocket wheel secured to the ring gear.

CONRAD J. ENGLERT.

